Electronic equipment produce waste heat that must be removed to avoid equipment malfunction. Removing the heat by circulating pumped water or fan driven air would consume power and further would create rapid temperature changes to produce detrimental thermal gradients in the equipment. Removing the heat by a closed loop thermal siphon would eliminate power consumption, but the siphoned medium would produce the detrimental thermal gradients in the equipment.
A capillary assisted loop thermosiphon apparatus is a closed loop fluid transport system that circulates working fluid by thermal siphoning assisted by capillary pumping. The working fluid is wicked into a capillary wick in evaporator that is heated, for example, by waste heat generated by electronic equipment. In the evaporator, the working fluid absorbs the heat to undergo a phase change from liquid to vapor. The term “liquid” herein refers to liquid phase working fluid. The term “vapor” herein refers to vapor phase working fluid. The wicking action and the increase in vapor pressure provide capillary pumping head pressure for displacing the working fluid forwardly in the heat pipe loop. The vapor circulates by capillary pumping to the condenser that condenses the vapor and dissipates the heat, and the liquid circulates to the evaporator by way of a liquid line. While heating the evaporator, it would be desirable to maintain the evaporator heating surface isothermal to eliminate potentially detrimental thermal gradients. A liquid saturated wick structure in the evaporator is desired, which would maintain the desired evaporator heating surface isothermal at the saturation temperature, while the evaporator is heated.
Further, the heat transport capacity of the capillary loop heat pipe is limited because the capillary pumping capacity is limited, as when low density vapor flow approaches the sonic limit. It would be desirable to increase the heat transport capacity of the capillary loop heat pipe by augmenting the capillary pumping capacity.